Workers Committee members are contesting the legitimacy of the National Union of Mineworkers

Johannesburg, South Africa (CNN) -- Nine mine employees were hurt Monday when Anglo American Platinum security guards shot rubber bullets to break up a confrontation between rival union groups at a mine in northwest South Africa, the company said in a statement.

The incident occurred at the company's Siphumelele mine in the Rustenburg area and involved members of the Workers Committee and shop stewards for the National Union of Mineworkers.

"As they were attempting to evacuate the NUM shop stewards who were trapped in their offices, three security personnel sustained minor injuries during this incident," the statement said.

All 12 injured employees received medical attention; none of the injuries was life-threatening, it added.

Police spokesman Brig. Thulani Ngubane said those hurt were taken to Bleskop Hospital. The shootings did not involve police, he said.

South African miners face uncertainty

"Workers committee members are contesting NUM's legitimacy at the mine and demanding that NUM vacate its offices," the company statement said. The company said it is trying to validate union membership at Rustenburg and the mines north of the Pilanesberg National Park.

Anglo American Platinum Limited, a member of the Anglo American plc Group, describes itself as the world's leading primary producer of platinum group metals, accounting for 40% of the world's newly mined platinum. Its mining, smelting and refining operations are based in South Africa.

Last fall, several major South African mining companies, including Anglo American, were involved in labor disputes with their miners that erupted in violence.

In October, police repeatedly clashed with protesters near one of Anglo American's mines, and the company fired about 12,000 striking workers who refused to attend disciplinary hearings.

The union did not immediately respond to a request for comment.

CNN's Kim Norgaard reported on this story from Johannesburg, and Tom Watkins wrote it in Atlanta.